loop4: detected capacity change from 0 to 8192 ================================================================== BUG: KCSAN: data-race in mark_buffer_dirty_inode / sync_mapping_buffers write to 0xffff8881405bfb50 of 8 bytes by task 10155 on cpu 0: __remove_assoc_queue fs/buffer.c:523 [inline] fsync_buffers_list fs/buffer.c:727 [inline] sync_mapping_buffers+0x165/0x7d0 fs/buffer.c:590 fat_file_fsync+0xad/0x100 fs/fat/file.c:195 vfs_fsync_range+0x10b/0x120 fs/sync.c:188 generic_write_sync include/linux/fs.h:2469 [inline] generic_file_write_iter+0x191/0x1c0 mm/filemap.c:4093 call_write_iter include/linux/fs.h:1868 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x47b/0x780 fs/read_write.c:584 ksys_write+0xeb/0x1a0 fs/read_write.c:637 __do_sys_write fs/read_write.c:649 [inline] __se_sys_write fs/read_write.c:646 [inline] __x64_sys_write+0x42/0x50 fs/read_write.c:646 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd read to 0xffff8881405bfb50 of 8 bytes by task 10149 on cpu 1: mark_buffer_dirty_inode+0x96/0x1c0 fs/buffer.c:623 fat_mirror_bhs+0x212/0x310 fs/fat/fatent.c:398 fat_alloc_clusters+0x973/0xa60 fs/fat/fatent.c:543 fat_add_cluster fs/fat/inode.c:108 [inline] __fat_get_block fs/fat/inode.c:155 [inline] fat_get_block+0x25c/0x5e0 fs/fat/inode.c:190 __block_write_begin_int+0x3b0/0xf50 fs/buffer.c:2064 __block_write_begin fs/buffer.c:2114 [inline] block_write_begin+0x7c/0x180 fs/buffer.c:2175 cont_write_begin+0x4c0/0x6f0 fs/buffer.c:2534 fat_write_begin+0x61/0xf0 fs/fat/inode.c:230 cont_expand_zero fs/buffer.c:2461 [inline] cont_write_begin+0x18f/0x6f0 fs/buffer.c:2524 fat_write_begin+0x61/0xf0 fs/fat/inode.c:230 generic_cont_expand_simple+0xad/0x140 fs/buffer.c:2425 fat_cont_expand+0x3a/0x160 fs/fat/file.c:223 fat_fallocate+0x182/0x1d0 fs/fat/file.c:301 vfs_fallocate+0x369/0x3d0 fs/open.c:324 ksys_fallocate fs/open.c:347 [inline] __do_sys_fallocate fs/open.c:355 [inline] __se_sys_fallocate fs/open.c:353 [inline] __x64_sys_fallocate+0x79/0xc0 fs/open.c:353 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd value changed: 0xffff888108a7b590 -> 0x0000000000000000 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 10149 Comm: syz-executor.4 Not tainted 6.4.0-rc6-syzkaller-00269-g1b29d271614a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023 ==================================================================